var fs = require('fs');
fs.open('123.txt', 'r', function (err, fd) {
    if (err) {
        console.error(err);
        return;
    }

    var buf = new Buffer(20);
    fs.read(fd, buf, 0, buf.length, null, function (err, bytesRead, buffer) {
        console.log(fd);
        if (err) {
            console.log(err);
            return;
        }
        console.log('bytesRead' + bytesRead);
        console.log(buffer == buf);
    });
})
